1. Data Transfer
2. Comments Regarding Emergency Funding
3. Review Of Diversion Pipe Hydrology And Design (To Tag By 8/22)

1. Data Transfer:

The EPA et. al. will provide me with copies of the following electronically (if possible):

• The SLERA report appendices as an excel file (received successfully).
  
• Jeannie Kornfeld/Bob Seal’s loading data, this is the only year-round loading data available.
  
• Chemistry of seeps at base of TP1, breakdown of types of iron (reduced or oxidized) and pH of these seeps.
  

2. Emergency Response Concerns

I raised 5 points in my Emergency Response review.  As anticipated, these are mostly being addressed.  They were:

1. Buttress: They have not performed calculations on residence time, but it is likely that the residence time will not be substantially changed (that means that chemistry of seeps will not substantially change), but it is likely that in the end, flows will be reduced from seeps.  They will look into active treatment during construction to reduce the chance of acid shock to the system per recommendation.
   


2. Foundation of buttress: They have mapped lateral extent of tailing fan, and have measured depth of tailing fan.  The thickest part of the fan is towards the base of TP1.  They plan on removing part of the tailing fan as part of building the buttress.  I requested that they try to remove the whole tailing fan as part of this action.  The horizontal and toe drains will all be diverted to a single outlet, and the water from that outlet will be directed so that it does NOT flow over the tailing fan.  The effluent will probably be directed into a settling pond or something similar for the iron to precipitate out, and then channelized through the remaining tailings.  The ANR will be responsible for O and M.  I strongly recommended that they try to remove the entire tailing ‘fan’ at the base of TP1.
   
   
3. Diversion: See Figure 1 and Table 1.  We talked about the diversions that could be performed by both the Town of Strafford and EPA.  Figure 1 shows recommended areas for Strafford to divert water (stars on map).  The most important areas are uphill and downhill of TP3 along Copperas Road (the class 4 road) and diverting the stream from subwatershed 1 that mixes with the TP3 tailings just upstream of Mine Road into the culvert nearby.  This is especially critical at the drainage of subwatershed 1 by the Mine Road, where a good part of the clean watershed mixes with the runoff from TP3.  The Town could berm, or divert the flow into the culvert that is a couple of hundred feet down the road.  The flow would still need to be diverted below the tailings that are upstream and downstream of the Mine Road culvert. 
   
   

Key: Blue line = diversion on east side of TP1/2 Red line = diversion on west side of TP1/2 Black line = Mine Road Thin blue line through watershed 4 and 7 -Jeep Road that will be used to bring fill to base of TP1 for buttress Thin Blue Line, watershed 1 and 9, Class 4 Copperas Road through TP3. Star = critical area for Town of Strafford to divert flow to keep clean water from mixing with tailings.

Table 1: Sizes of sub-watersheds (ADL)            

Sub watershed	1	2	3	4	5	6	7	8	9	10	11	12
Total area (acres)	86	30	26	26	15	7	27	4	2	29	22	6

4. Slope Stabilization: I gave a copy of the report on the 1989 NRCS plantings to everyone, they were not familiar with it.  Jason will check with John Dickerson (NRCS) on exact locations of the test areas.  As I remember, the upper terrace plantings (no soil added, only fertilizer and lime) is on TP2, but  Jason will check with John.  I remember an area there with thick grass cover, but no one else did. 

I recommended that since the best time to plant is September that a pilot plot be hydromulched with the NRCS recommended seed mix, 10-10-10 and limestone as amendments.  The best places for this would be: the ditch at the base of TP1 on the west side (red line on the map), the steep slopes of TP1 on the same side, and the steep slopes of TP2.  Any or all of these areas could be planted as a test plot.  The advantage of doing the ditch at the base of TP1 is that it is a critical area to stabilize, while mass failure of the tailing pile on that side is not as much of a concern as failure due to piping, or clogging of the adit, if that ditch was severely eroded, it could undermine that side of TP1 causing failure.  Hydro-mulching this as a test plot is cheap (under $500 an acre for materials).  The county garage of VTRANS may be willing to donate the use of a hydromulcher if they have one (most counties do, I believe). 

I didn’t get any encouragement for doing test plots per NRCS recommendations, but believe that a pilot project is cheap and would give good information.  Hydro-mulching could also be performed on all disturbed surfaces as part of the emergency action.  I strongly urge the CAG to request that the ditch on the west side (red line) be hydro-mulched as part of the emergency action, and the slopes of TP1 that are adjacent to the ditch that will not be buttressed.  If some money could be saved on the emergency action (see comments below) than that could free up some money for slope stabilization and hydro-mulching (which can be justified as preventing erosion of tailing dam) under emergency action.

5. Diversion Pipe: I recommended that some sort of active treatment be considered during construction of the diversion pipe for the pond.  It may be as simple as spreading lime on top of the freshly exposed and disturbed tailings (as ACE suggested), or it may be an active dosing system downstream.  Any construction brings an opportunity for acid shock, and typically active treatment occurs during construction.  The preliminary drawings and description of the diversion pipe were presented.  The EPA said that the emergency folks are not usually too interested in things like ‘acid shock’, but focus more on immediate threats.
   

3. Review Of Diversion Pipe Hydrology And Design (To TAG By 8/22)

In summary, the diversion pipe is a 36 inch diameter plastic culvert that is about 1000 ft. long.  It will take the water from the base of the pond, around the east side of the pile, and north to end in the existing stream channel on the Northeast corner of TP1.  There will be some sort of energy dissipation (large rocks) installed where the culvert meets the stream channel.  The site will be accessed either across TP1, or across the Jeep Road.  If the Jeep Road is used, it will be improved with an eye towards keeping the clean part of the subwatersheds number 4 and 7 from mixing with TP1. The Jeep Road is proposed as the ‘main drag’ to bring in buttress material in 2004. 

Parallel to the culvert will be ~1000 feet of  4 inch perforated drain tile to intercept groundwater from the clean part of the watershed. 

Both the 36” and 4’ pipe are proposed to be laid in washed sand (See comments below) and will have clean-outs at regular intervals (about every 300 feet).  Most of the pipe will be fairly flat (0.5% slope) for about 700 feet, and the last 300 feet will be at a 12% (steep) grade.  Both the culvert and draintile will be in a channel that is graded flat and is about 15’ wide with 2:1 side slopes.  This wide channel will serve as a spillway for any flow that the culvert can not handle (really big rain storms).  The upper (flatter) part of this ditch/spillway channel will serve as a road during 2004 for the construction of the buttress.  The steep (12%  slope) part of the channel will be protected with rip-rap.  This rip-rap should probably be as big as possible (>20 inch diameter on the middle (B) axis.), especially at the top of the slope to reduce the chance of headcutting.  The side slopes of the ditch.spillway channel will be between 2:1 - 2.5:1 (pretty gentle gradient, not liable to erode much).  This means that (depending on existing topography) that a swath of trees as much as 70 feet wide and 1000 ft. long would have to be clear cut (about 1.7 acres).  I don’t know what the plans are for the cordwood/lumber/pulpwood that would be clearcut from this area.  Up to 7 ft. of  glacial till will be excavated, I imagine this will be stockpiled somewhere for use in berming/channel diversions, but don’t know for sure. This entire trench will be underlain with erosion fabric and appears to be filled with rip-rap to a depth of 2 - 2.5 feet.  This is a lot of rip-rap, thousands and thousands of yards, I have not seen the spec sheets, but this is a lot of stone.  It appears that in the end (after the upper part has been used as a road for the buttress) that the entire 1000 ft. of channel will be lined with rip-rap (because it is considered a spillway), this may not be necessary if the stone at the top of the steep slope is sized on the large side (to prevent headcutting) at this vulnerable location.

The culvert and draintile are predicted to be part of the final closure.  The ditch/spillway channel may need re-grading or may not be used as part of the final berms/diversion.  Since the ditch/spillway may not be part of the final closure I’d like them to look at an alternative that may do the job effectively for the predicted period of time of use (5 – 10 years).  Perhaps the trench could be scaled down (less rip-rap, no use of filter fabric etc) if the useful life of this trench is relatively short.  The money saved could go towards hydro-mulching and small diversions as discussed above.

There is a limited area that will be re-graded near the base of the pond to keep ‘clean’ water from mixing with tailings.  The decant system will eventually be closed, but a portion of it should remain as a horizontal drain in TP1.

I’d recommend looking at down-sizing the ~35 ft. wide 12% grade part of the channel.  The bankfull widths of the existing stream (downstream of the culvert under the tree) was around 7 feet.  Since steeper channels can be narrower (cause the water travels so much faster), it may be possible to reduce the width of this channel from 15’ with ~10 ft. of 2:1 slopes on either side of the 15’ channel (unless it is being used as part of the road (which I doubt, but is not clear in the design overview).

OTHER ITEMS DISCUSSED

Review of Field Sampling Plan:
URS will provide me with their comments on the Field Sampling Plan soon.  It appears that many of my comments have already been addressed, and that some data has already been gathered.

Review of Passive Treatment report:
It seems that there was general agreement that the passive treatment report needed updating and that work is currently in progress.  We should receive it when it is complete. I recommended that since URS does not have in-house capability for passive treatment, and that - since it is likely that a Successive Alkalinity Producing System (SAP) will be part of the final design  -(per the EE/CA) at TP1, that URS hire Damariscotta for the passive treatment portion of the work.  Damariscotta (as you may remember) invented the SAP design, has over 20 years of experience with SAPS.  URS currently contracts with Damariscotta on another unrelated project.

COMMENTS:

Cost-Saving:
The CHC requested that I review the plans with an eye towards making the best possible use of the money (3 million in emergency funding) so that not only will the tailing pile be stabilized, but all possible (justifiable) efforts to remediate the site be accomplished at the same time.

In general, I think my biggest concern there is not in the design, but in the details of the design.  There are places where the Cadillac version, might be able to be addressed with the Ford version.  This could free up money that could be used for more work that both addresses remediation and emergency needs at the same time.  I would request that the CAG ask for an alternatives analysis that presents both the Cadillac and Ford versions (ok. BMW and Volkswagen).  I would never suggest a design that has technical drawbacks, but there could be some flexibility in the details that could reduce trucking costs and truck traffic, two things that heavily impact the Town and the overall cost of the project.  An informal alternatives analysis would help to address this, it could look at local stone vs. non-local stone, local vs. trucked borrow, reductions in overhead and fixed costs etc..

For example:

1) The plan is to bed both the draintile and 36” culvert in washed sand.  Washed sand (from Lebanon, NH) is $42 a yard delivered.  Typically in Vermont (calling on my many years in construction) drain tile is bedded in peastone, and then covered with hay, fiberglass insulation, old blue-seal bags, or a filter fabric.  It may be possible to limit the use of sand to the area directly around the pipes and use stone or unwashed sand.  Perhaps, this type of alternative analysis could save money which could then be used to scrape up more of the tailing fan at the base of TP1.  Scott Acone notes “Stone is not an acceptable substitute for sand without additional measures to prevent the possibility of piping within the backfilled culvert area.  Compaction around large diameter pipes is difficult.  Sand backfill will prevent this piping.  Other measures such as installing concrete cutoff collars, would be necessary with stone materials, and, will increase costs and truck traffic associated with concrete trucks”.  The sand also may not make the best base for the road/spillway channel that will be taking quite a bit of heavy truck traffic.

2) The channel for the culvert is 15’ wide, with a 2:1 slope, and lined with rip-rap and native soil.  The steeper sections of the channel are lined with rip-rap.  One option is to limit the disturbance on the steeper section of the channel (so that it doesn’t need to be so wide (unless it is part of the road) and use rip-rap from stone quarried on or near the site.  Since water travels faster on steeper slopes, the size of the spillway channel could possibly be reduced. No riprap has been specified for the upper (shallower) channel at this time.

Rip-rap:
I called Dick Josler to see if he was still interested in quarrying stone from his property, and if the EPA et. al. had contacted him.  The answer was yes, and no.  He hasn’t heard from the EPA, and he is interested in quarrying stone.  Quarrying local stone would save money in truck traffic, wear and tear on roads, and support local people.  I don’t know if his stone would be the ‘best’ stone for the job, but if it is not, there may be a trade-off with the reduced cost, reduced trucking etc.  There will be a lot of trucking, and a lot of stone required for the buttress.  Apparently the Superfund process trumps Act 250, and material can be quarried for the project without an Act 250 permit, so that material could be quarried on this site this fall if needed.

Local Contractors:
I asked ACE about using local contractors.  Due to the nature of the contracts, the contractor that they will use for managing the construction associated with work is Conti Environmental based out of Concord, Massachusetts.  He has an established contract with the Corps, has all the necessary bonding etc.  He is likely to sub out the work, and will likely hire local contractors.  The project will not go out to bid, but local contractors interested in the buttress, diversion pipe etc.. should contact Scott Acone at the Corps at 978-318-8162.  I heard from Dick that there were several contractors that would have liked to have had a chance to work on the site.

Overhead and Fixed costs: These two costs; overhead and fees are part of how the ACE does business.

Overhead costs (or the operating cost for the company to cover such things as utilities, rent, administrative support, etc.) are determined by an audit performed by the Government Accounting Office (GAO) as part of this type of Corps’ contract.  This rate varies annually and is not negotiable.

Fee (or profit) is a negotiated cost for these contracts.  Fee usually ranges from 5% to 12% depending upon the complexity of work, the type of work, the risk assumed by the contractor, and several other factors discussed in the Federal Acquisition Regulations.  Fee is a necessary cost for Government contractors to cover costs excluded from overhead by federal regulations (such as advertising and marketing) as well as to provide incentive for the company to stay in business and complete their work.

The Corps independently determines an appropriate fee for the work being contracted and negotiates a fee rate with the contractor that is in the best interest of the Government (i.e., is fair to all parties).

My strongest recommendations are to:

1) Look carefully at existing roads to do as much diversion as possible along existing roads. This is true for EPA and the Town of Strafford.

2) Since it is unclear whether or not there will be more money in the future, try to get the hydro-mulching/ slope stabilization and removal of the tailing fan at the base of TP1 done under the emergency funding measures.  Call it erosion and sediment control.

3) Slope stabilization is especially critical on the west side of TP1, that ditch/channel is a bit scary,  very eroded.  Although failure on that side is not predicted, if that ditch washed out, that west side of the pile could collapse contributing a huge sediment load.  The buttress will wrap around some of the west side, but not the whole west side. I am not sure how they plan to deal with the ditch at the base, we will see the plans for that this winter sometime (is my guess).  Stabilization of this ditch is a high priority and should be funded under this action, including stabilizing the slopes leading to this ditch/channel.

4) Look at the Ford version, perhaps locally quarried stone (while perhaps not the best), may have trade-offs that will make the project more affordable, and use more local resources (contractors, local landowners etc…, that could reduce impact on town roads etc).

5) See if the CAG has any input on fixed fees and overhead, and use of local contractors.  This may free up money for more implementation of slope stabilization and diversion.

6) Implement active treatment during construction to avoid ‘acid shock’.

7) If the chemistry of the seeps can be preserved (by not flowing over the tailings), than -  using the air shaft as a proxy - a lot of the loading from the seeps may be able to be mitigated with oxidation and settling ponds at the outlet of the seeps.  My current understanding is that these ponds will be part of the emergency measure.

8) Keep the culvert under TP1 (that exits by the tree) and turn it into a horizontal drain.  Since horizontal drains will be part of this measure, it makes sense to keep an already existing drain (it may need to be lined with perforated 4” tile and seated in flowable fill.

9) Support stormwater mapping of culverts, ditches and roads to see where low-cost improvements can be made to prevent ‘clean’ water from mixing with tailings.

10) Use Best Management Practices for Erosion and Sediment Control (which may include hydro-mulching) areas of the tailing piles that are eroding.

11) Request that the fee structure be set at the lowest level of profit, thus ensuring more money for implementation.

I have friends who have been working on a large copper mine in Montana, (for about 15 years now), and no remediation has been accomplished.  At this point - with funding unclear for future work, I recommend that every possible action that could be conducted under the scope of this emergency funding that could remediate the site (and be justified) be implemented. 

Scott Acone notes that “the scope of what the Corps can accomplish is determined by EPA.  For the emergency removal, only those activities that go to eliminate the current risk to downstream residents are considered within scope.  Any cost savings associated with accomplishing this effort will not necessarily go towards completing additional, out-of-scope activities such as hydromulching and diverting surface runoff along roadways….”

Let me know if you have any questions.  I will get the final design on the diversion pipe by August 22nd (when I get back from vacation).  I will try to comment on it at that point.  Scott Acone’s comments are incorporated into this version. 

Lori
Loribarg@together.net